• Biomedical Science Letters
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• v.10 no.4
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• pp.485-493
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• 2004

In the current field of Medical Informatics, the information increases, and changes fast, so we can access the various data types which are ranged from text to image type. A small number of technician digitizes these data to establish database, but it is needed a lot of money and time. Therefore digitization by many end-users confronting data and establishment of searching database is needed to manage increasing information effectively. New data and information are taken fast to provide the quality of care, diagnosis which is the basic work in the medicine. And also It is needed the medical database for purpose of private study and novice education, which is tool to make various data become knowledge. However, current medical database is used and developed only for the purpose of hospital work management. In this study, using text input, file import and object images are digitized to establish database by people who are worked at the medicine field but can not expertise to program. Data are hierarchically constructed and then knowledge is established using a tree type database establishment method. Consequently, we can get data fast and exactly through search, apply it to study as subject-oriented classification, apply it to diagnosis as time-depended reflection of data, and apply it to education and precaution through function of publishing questions and reusability of data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.24-27
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• 2001

Nowadays, increasing demand of the customized products has led to an increased usage of rapid prototyping in the product development. However, the acquisition price of a rapid prototyping equipment is still too high that not every body can afford to buy one. To offer a wide access to the users who need physical prototypes, a connection of the rapid prototyping equipment to the Internet is a viable step. It would allow a large group of customers all over the world to use the manufacturing capability of a service provider offering this kind of manufacturing service. To realize how such an e-manufacturing concept can look like, a LOM-type 3D printer developed at KIST has been used as test site and connected to the Internet. A possible user can log on to the server of the equipment and view his STL file and start the building operation from a remote place. To see whether the operation runs properly, a CCD camera is used to transmit the actual state of operation online. The result so far proves the feasibility of rapid prototyping on the Internet as well as an order-adaptive manufacturing system via web.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.2
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• pp.79-83
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• 2009

Streaming Technology can support the real-time playback without downloading and storing multimedia data in local HDD. So, client browser or plug-in can represent multimedia data before the end of file transmission using streaming technology. Recently, the demand for efficient real-time playback and transmission of large amounts of multimedia data is growing rapidly. But most users' connections over network are not fast and stable enough to download large chunks of multimedia data. In this paper, we propose an intelligent IP streaming system based on personalized media service. The proposed IP streaming system enables users to get an intelligent recommendation of multimedia contents based on the user preference information stored on the streaming server or the home media server. The supposed intelligent IP streaming system consists of Server Metadata Agent, Pumping Server, Contents Storage Server, Client Metadata Agent and Streaming Player. And in order to implement the personalized media service, the user information, user preference information and client device information are managed under database concept. Moreover, users are assured of seamless access of streamed content event if they switch to another client device by implementing streaming system based on user identification and device information. We evaluate our approach with manufacturing home server system and simulation results.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.5
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• pp.269-277
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• 2018

NAND flash memory has widely been used because of non-volatility, low power consumption and fast access time. However, it suffers from inability to provide update-in-place and the erase cycle is limited. The unit of read/write operation is a page and the unit of erase operation is a block. Moreover erase operation is slower than other operations. We proposed the Adaptive Garbage Collection (called "AGC") policy which focuses on not only reducing garbage collection process time for real-time guarantee but also wear-leveling for a flash memory lifetime. The AGC performs better than Cost-benefit policy and Greedy policy. But the AGC does not consider the operation characteristics. So we proposed the Advanced Adaptive Garbage Collection (called "A-AGC") policy which considers the page write operation count and block erase operation count. The A-AGC reduces the write operations by considering the data update frequency and update data size. Also, it reduces the erase operations by considering the file fragmentation. We implemented the A-AGC policy and measured the performance compared with the AGC policy. Simulation results show that the A-AGC policy performs better than AGC, specially for append operation.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.1-10
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• 2018

In cognitive radio (CR), secondary users (SUs) are able to sense the absence of primary users (PUs) in the spectrum. Then, SUs use this information to opportunistically access the licensed spectrum in the PUs' absence. In this paper, we present an implementation of real-time video transmission with spectrum-sensing between two points using GNU Radio and a National Instruments 2900 Universal Software Radio Peripheral (USRP). In our project, spectrum-sensing is implemented at both transmitter and receiver. The transmitter senses the channel, and if the channel is free, a video signal (which could be a real-time signal from a video file) will be modulated and processed by GNU Radio and transmitted using a USRP. A USRP receiver also senses the channel, but in contrast, if the channel is busy, the signal is demodulated to reproduce the transmitted video signal. This project brings in several challenges, like spectrum-sensing in the devices' environment, and packets getting lost or corrupted over the air.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.70.3-70.3
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• 2018

외계행성 탐색시스템의 망원경-카메라 제어 시스템 및 소프트웨어 구성과 관측 유틸리티에 대해 소개한다. 망원경 제어 소프트웨어는 천문 위치보정, 포인팅, 돔 회전 등을 담당하는 PC-TCS 프로그램, 망원경 적경-적위 축 서보 제어를 담당하는 full-closed loop PID 컨트롤 프로그램, 포커서, 필터박스, 돔 셔터, 주경냉각, 온도 모니터 등의 보조 시스템을 제어하는 AUX controls 프로그램으로 구성된다. 카메라 제어 소프트웨어는 모자이크로 구성된 여러 CCD를 각각 독립적으로 제어하는 IC(Instrument Control) 패키지와 이들을 총괄 제어하는 ICS(IC Science) 패키지로 구성되며 망원경과 카메라 소프트웨어의 인터페이스 역할을 하는 TCS Agent 프로그램이 포함된다. 관측 진행을 돕는 유틸리티로서 관측제어 명령어 입력 및 관측 스크립트 구동 기능을 제공하는 OBS Agent 프로그램과 가이드 CCD를 이용한 시상 모니터링 및 자동초점조정 프로그램을 개발하여 활용하고 있다. 각 소프트웨어는 UDP, TCP/IP, RS-232, Redis server 등 다양한 인터페이스를 통하여 서로 통신하며, CCD 영상 자료 전달을 위해 RAM(Random Access Memory) 디스크와 Network File System(NSF)을 이용하고 있다.

• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.555-560
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• 2014

This paper proposes the data security technology for the desktop virtualization environment using the separated software execution method. In the virtual environment where allocates separate VMs to the users, there is a benefit that the programs in one guest machine are isolated from the programs running in another guest machine, whereas in the separated execution environment that supports application virtualization, the isolation is not offered and it causes the data security problem because the applications are executed by the one root privilege in the server. To solve this problem, we provides the data security method using the server storage filter, the viewer filter, and the file mapping table in this paper.

• Journal of Korea Multimedia Society
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• v.18 no.12
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• pp.1501-1508
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• 2015

In this paper, we describe a case study to improve performance through the load testing of multi-tired system for financial accounts before the system opening. The load test was conducted after the data collection tools(Performance Monitor, DB PSSDiag) were installed. By analyzing the collected log, we were able to identify the main sector requiring performance improvements among the presentation tier, web tier, business logic tier and data tier. The ASP.NET server-down on the web tier could be improved by modifying the parameter values in the configuration file. Some server downs occurred on the business logic tier when a large number of users access at the same time, were more difficult to be solved. By analyzing the hang-dump at the server-down time, we were able to find a process that caused the problem. and we had to modify the relevant codes. For major performance improvements of the data-tier, indices of some queries was optimized by using the built-in DBMS query analyzer, after analyzing the log of long-response-time queries. The problems and solutions considered in this case study will be a reference for the performance improvement of a multi-layer system with the similar structure.

• Journal of Information Management
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• v.33 no.4
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• pp.85-105
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• 2002

The purpose of this study is to review the expanded role of authority files, which uses the Knowledge Organization System(KOS) to organize contents and manage the collections in digital libraries. The KOS plays a role as a bridge between the users' information needs and materials by providing links between catalogs and digital resources on the web and supporting retrieval of the relevant items. It is described how a KOS can be used to link a digital resource to related materials, to provide more descriptive records for entities, and access to relevant physical objects.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.60-67
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• 2005

A cluster consists of a collection of interconnected stand-alone computers working together and provides a high-availability solution in application area such as web services or information systems. Content-based load distribution for web server clusters uses the detailed data found in the application layer to intelligently route user requests among web servers. In this paper, we propose a content-based load distribution algorithm that considers cache hit and load information of the web servers under the web server clusters. In addition, we expand this algorithm in order to manage user requests for dynamic file. Specially, our algorithm does not keep track of any frequency of access information or try to model the contents of the caches of the web servers.